Sheriff Bill Elder says deputies and police who wound up in a gun battle at a Colorado Springs apartment complex Monday were wearing protective vests.
Despite that protection, one deputy was killed and three others were wounded.
So what happened?
In the absence of detailed and official reports it's hard to say. But no protective vest can stop every bullet and all vests are not created equal.
Police agencies seldom use the heaviest body armor - military-style gear that can stop rifle rounds. That's because the heavy armor, called Type IV in police circles, includes steel plates and weighs as much as 40 pounds.
Instead, most police opt for lighter armor. That consists of layers of Kevlar fabric and can stop most pistol rounds. The Kevlar armor is light and pliable, allowing police to move freely.
Light or heavy, though, body armor provides limited protection.
The armor is built to protect the torso, shielding the heart, lungs and other vital organs from damage.
While the military has additions that protect arms and the groin, they are uncommon in civilian use. That means police go to work with most of their body unprotected.